If you want to be certain that you do no harm when lifting and placing SMT devices, use good quality liquid flux on the joints/ board before you start. Pre heat the board to 100-150 degrees for a minute or so, and then tickle the pins, or in the case of BGA, the entire part, with either IR or a Hot Air wand until you reach fluid point, which will be the melting point of your solder. Remember lead free solders have a higher temperature melting point. Then simply lift the device away and allow the board to cool. In any case do not go over the rated permissible temperature of the device or you risk damaging it, or worse, scorching the board or delaminating the pads and track. Clean up using a low powered solder pump/ sucker with a silicone nozzle. Do not use one with a hard nylon nozzle or you will pop pads left right and centre with the recoil. If you're good with it you could use solder wick, but a word of caution, on fine pitch pads, never ever remove the heat without removing the wick at the same time from the joint or you will tear the pads clean off the board. Also when using Hot Air, if there are other smaller parts in close proximity to the device you are removing/ replacing, use some strips of Kapton tape around the device to stop you blowing them right off the board. Nothing worse than making a great job of a QFP Flat Pack rework then realising there's no resistors around it anymore! SMT glues have a breakdown/ melting point of around 150 degrees, so no problem there either as you will be well above that when the joints are fluid.
Always fully clean any old flux off the board before applying new flux prior to device placement.
The best advice I can give you is take your time, don't rush things. Work in good light, a magnifier also helps you see what's happening, and use the right tools for the job. Apply only enough heat to get the job done with ease. Don't be tempted to turn the temperature up beyond the max that the device can handle, particularly in the case of expensive or sensitive chips, just be inventive in the way that you get the device to temperature in the shortest period of time.
Pre heating the board will greatly help you quickly get the solder fluid without damaging the board or device. Never lever at a device, try to twist it off, or apply any kind of upward pull on it until the joints are fully fluid or you risk tearing up pads and track. When cleaning up the board be careful with wick on fine pitch pads, and never use hard nylon nozzles on solder suckers.
rgds